JP2012134967A - System and method for power grid communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system and method of data communication for a power grid to determine available wired and wireless modes of data transmission and available routes in these available wired and wireless modes.SOLUTION: The system and method includes determining available wired and wireless modes of data communication and available routes in the available wired and wireless modes. A weight is allocated to each of the available routes, and a final route for communication is determined based on an objective function.

Description

  The present invention relates to systems and methods for power grid communications.

  Smart grids use digital communication and control technology to deliver electricity to consumers while minimizing financial costs, conserving energy and increasing reliability. When properly designed, smart grids have a major impact on improving a wide range of aspects in the power generation and distribution industries. Examples include self-healing, high reliability, resistance to cyber attacks, application to a wide variety of types of distributed generation and storage systems, optimized asset allocation, and minimizing operational management costs, and Includes high-resolution market control that incorporates advanced instrumentation and demand response.

  An important component of the smart grid is distribution automation (DA). DA refers to monitoring, protection, control, and communication functions performed between a substation and a premises or a customer. Protection and opening and closing are important functions of DA. DA's protection system automatically and properly 1) detects and disconnects distribution grid faults, 2) power distribution substations adjacent to faults provide electrical services to customers disconnected by fault isolation equipment It must be possible to determine if it has sufficient connectivity and capacity to be restored, and 3) be able to operate the switch to connect nearby substations and restore electrical service. Today, most DA protection devices, such as reclosers, do not communicate with each other and operate independently without knowing the status of other protection devices other than their location and the status of the grid. As a result, failure isolation is not optimal, and more customers than expected need to stop service at the time of failure.

US Patent Application Publication No. 2010/0152910

  For these and other reasons, embodiments of the present invention are needed.

  In accordance with one embodiment of the present invention, a data communication system and method for a power grid is provided. The system and method includes determining an available wired mode and a wireless mode for data communication, and determining available routes in the available wired and wireless modes. A weight is assigned to each available route, and a final route for communication is determined based on an objective function.

  The features and aspects of embodiments of the present invention may be better understood by reading the following detailed description with reference to the accompanying drawings. Like reference numerals represent like parts throughout the drawings.

It is a schematic representation of the power poles used in the power distribution system. Fig. 2 is a schematic representation of a recloser loop scheme with two feeders. 1 schematically illustrates a recloser system 100 according to an exemplary embodiment of the present invention. 5 is a flow diagram illustrating a method of communication in a power grid according to an exemplary embodiment of the present invention. 1 illustrates a power grid communication system according to an exemplary embodiment of the present invention.

  When introducing elements of various embodiments of the present invention, the articles “a”, “an”, “the”, and “said” mean that one or more of the elements are present. Is intended. The terms “comprising”, “including”, and “having” are intended to be inclusive and that there may be additional elements other than the listed elements Is intended to mean

  As used herein, the term “module” refers to software, hardware, or firmware, or any combination thereof, or any system, process that performs or facilitates the processes described herein. Or refers to the function.

  Power generation equipment, transmission lines, and distribution lines need to be protected from temporary and permanent failures that can occur in the wires and the associated short circuits. These obstacles can cause power system disruptions, serious and expensive equipment damage, and personal injury. In addition, large scale power outages caused by these failures can cause anger among consumers who expect reliable and reliable utility services. For example, assisting in disconnecting wire faults and initiating disconnection by actuating (ie, opening) circuit breakers, sectionizers, and reclosers is the function of fault protection devices such as fuses, protective relays, and reclosers It is. In addition, power distribution operators can use the automatic power recovery components, including but not limited to tie switches, in the event of protection failures or other system malfunctions to provide electrical services to consumers. Is automatically recovered.

  Each recloser includes, but is not limited to, for example, a power line carrier, a land line telephony, an electric utility radio, WiFi, WiMAX, and a cellular phone. Equipped with sufficient communication equipment to communicate via a set of predetermined wireless and wired systems.

  FIG. 1 shows a power pole 10 used in a power distribution system to suspend an electric wire above the ground. An automatic recloser device 12 having a control device 14 is attached to the utility pole 10 to protect the distribution system. The control device 14 can be arranged separately from the recloser device 12 as shown, or can be integrated with the recloser device 12. The function of the recloser device 12 is to provide life safety, protect equipment and minimize power distribution outages caused by temporary or permanent failures. Typically, during a fault, the current carried by the wire suddenly increases due to a short circuit condition. The recloser detects this increase in current and opens its circuit breaker, thereby interrupting the current flow to protect the distribution system components and other equipment connected to the distribution system. Since many fault situations are temporary, the recloser is designed to close after a short period of time and determine if the fault is still occurring. If the recloser is closed and an increase in current is still occurring, the recloser will reopen. Such an open / close transition can occur quickly several times before the recloser remains open if the fault is permanent. For example, if a lightning strike occurs in a power distribution system during a thunderstorm, the power to the customer may be temporarily interrupted for a few seconds, and the resulting recloser behavior causes lighting and equipment to be turned off on the customer premises (recloser Open), then turn on (recloser closes).

  FIG. 2 illustrates a recloser loop scheme 30 according to one embodiment of the present invention. The recloser loop system 30 includes substations 46 and 48 and has two feeders 32 and 34 and consumers 50, 52, 54 and 56. The power distribution feeders 32 and 34 are connected via an interconnection recloser switch 40. During normal operation, the interconnecting recloser switch 40 is open and the distribution substations 46 and 48 provide electrical services to the distribution feeders 32 and 34, respectively. The recloser loop system 30 includes four feeder reclosers 36, 38, 42, 44 and an interconnecting line recloser 40 that cooperate with each other. Reclosers 36, 38, 42, 44, and 40 and / or substations 46 and 48 include a controller, which will be described in detail below.

  In operation, when the systems are first deployed and operational, reclosers communicate with each other via a predetermined communication network available locally. Each recloser automatically examines other locally available alternative data communication systems with a pre-programmed set of instructions. Multiple reclosers work together to determine the available alternative paths and the cost functions of their families according to a preprogrammed objective function. The recloser network creates a ranking of all available communication paths based on their system cost and stores this information in each recloser. The recloser network periodically checks locally available communication paths and updates the ranking. The recloser also communicates with substations 46 and 48 to determine the capacity of each substation. This information is used to determine whether in the event of a failure, each substation can supply power to other feeder consumers through a process known as backfeeding. This information is also stored in each recloser. When a permanent failure occurs, for example at F1, the recloser 44 operates according to its reclosing sequence, locks out, and transmits information about its status and failure status to other reclosers via the communication path. The recloser 44 transmits this information using the communication path previously determined by the objective function. Accordingly, the recloser 44 can transmit data via one or many paths simultaneously. After recloser 44 locks out, consumers 50 and 52 lose electrical service and experience a power outage. A feeder recloser control device (not shown) on the recloser 42 and the interconnection switch 40 receive the information transmitted from the recloser 44. The interconnection switch 40 can also detect a loss of the feeder 32 voltage. Based on this collected information, the recloser 42 opens. When the substation 48 has a capacity sufficient to reversely feed the customer 52, the interconnection switch 40 is closed and the substation 48 restores the electrical service to the customer 52. In this way, faults are effectively isolated and only customer 50 loses electrical service.

  FIG. 3 illustrates a recloser system 100 according to one embodiment of the present invention. System 100 includes a substation 101 that delivers power to a residential area 102 and an industrial area 103. According to one embodiment of the present invention, any wireless network available in the vicinity of the recloser system can be used for communication between the various reclosers. For example, in one embodiment, the wireless network comprises a dedicated wireless link (not shown) used for communication between reclosers.

  In the exemplary embodiment shown in FIG. 3, the wireless network comprises a vehicle-to-vehicle ad hoc network (VANET) 106. The VANET 106 is a technology for constructing a mobile network by using a wireless device in a moving car as a network node. The wireless device can include commercially available data communication technologies, including but not limited to WiFi and WiMAX, with protocols designed for inter-vehicle communication. The VANET 106 can use any participating vehicle as a wireless router or node and connect vehicles that are within about 100 to 300 meters of each other, thereby building a wide area network. When a vehicle leaves the recloser's radio range and leaves the network, other vehicles join and connect the vehicles together so that a local mobile ad hoc network is built near the recloser network formed from recloser 105 be able to. It will be appreciated that in this embodiment, if the VANET 106 has a reliable network with sufficient capacity, the reliability of communication between the reclosers 102 can be improved. Other wireless networks that can be utilized include, for example, Wireless Fidelity (WISM), World Wide Interoperability for Wireless Access (WIMAX), Global System for Mobile Communications (GSM) 80, Wireless System for Mobile Communications (GSM), and Wireless System for Mobile Communications (GSM). Includes Personal Area Network (6 LowPAN) and Routing Over Low power and Lossy networks (ROLL). In one embodiment, as needed, the most important information or data is transmitted via a dedicated electric utility radio, and less important information or data is transmitted along other wireless networks. The importance of the information is determined by the user or by any suitable method.

  As shown in the figure, there can be a plurality of routes with which the feeder recloser can communicate with each other. Thus, according to one embodiment of the present invention, each available route is weighted and a specific route can be selected based on a user-determined objective function or a pre-programmed objective function. . The weight may be determined by various factors including, but not limited to, communication cost and communication speed. Similarly, the objective function may include critical customer indicator minimization, including but not limited to financial costs, data transfer delays, or combinations thereof. The objective function includes a power distribution reliability index including a system average power interruption duration index (SAIDI) and a momentary average power interruption event frequency index (maifi), and a minimum power distribution reliability index including a power average reliability index such as a system average power interruption event index. SAIDI is a value obtained by dividing the total power outage time of all customers by the number of customers, and maifi is a value obtained by dividing the number of power outages longer than a specified time by the number of customers. Combining critical customer indicators and distribution reliability indices, we can get the total system cost minimized by the objective function. In another embodiment, packets of communication data may be distributed and transmitted over various paths depending on availability and desired objective function.

  Note that there can be multiple routes in one type of communication method itself. For example, when data is transferred over a wire or wired communication method, there may be multiple paths or communication links from one recloser to another. Thus, in one embodiment, multiple routes in one communication method itself are selected based on the optimization function. For example, a network routing indicator can be provided for various communication links to indicate the cost of routing through that link. A low cost link is preferred over a high cost link. These indicators can be defined by the user, and in one embodiment, a link that follows the same route as the shortest power line is given any cost that is less expensive than a route that excludes the shortest route of wires. This forces the data to flow along a specific optimal path. Geographic information system (GIS) information can be used by the system to determine which electrical link provides the shortest route.

  In another exemplary embodiment, data may be transmitted using a Media Access Control (MAC) protocol based on Global Positioning System (GPS) and Geographic Information System (GIS) information. The MAC provides an addressing and channel access control mechanism that allows several network nodes to communicate within a multipoint network. In one embodiment, the MAC protocol layer determines when to transmit a data packet based on information from GPS and GIS. GPS provides information about the location of the radio or any other node, and GIS provides information about the radio environment. Thus, information from GPS and GIS can be processed to provide an estimate of the range and power of radio frequency (RF) data that needs to be transmitted for successful communication between nodes. In addition, GPS and GIS information can be used to provide a framework that can deterministically calculate MAC transmission timing, thus avoiding collision overhead. The purpose of this method is to avoid data transmission collisions with neighboring radios while scheduling transmissions quickly enough to meet the required data transmission load. In another embodiment, additional information obtained from GIS, including topographic, vegetation, and building density information, further refines the required RF transmitter power level. In general, most MAC protocols are distributed by randomly backing off upon collision detection. However, in the present embodiment, considering that the radio is for outdoor use and located at a fixed location, transmission of the MAC layer is scheduled based on the location obtained by GPS and the local environment information from the GIS database. Is done.

  In another exemplary embodiment, in order to further improve communication between reclosers, a multicast group can be formed in which a single packet transmission reaches all receiving nodes simultaneously. All nodes along a given wire can belong to a single multicast group. As will be appreciated by those skilled in the art, multicast can be used for data transfer between various nodes. It should be noted here that a node can mean a recloser, a radio, a car in a VANET, or other communication point of a wired or wireless network. Data is transmitted simultaneously to multiple nodes or reclosers at the originating node, i.e. from the recloser where the data needs to be transferred, sharing a common path through the network. As a result, communication is faster than transmitting the same packet to a set of nodes at once.

  FIG. 4 shows a DA communication method 200 for the power grid. The method includes, at step 202, determining an available data transmission mode between the source node and the destination node. This available mode may include a wired communication mode or a wireless communication mode. For example, wired communication modes include wired communication links through wires, and wireless communication modes include power grid wireless links and other opportunistic routing such as WIFI, WIMAX stations, GSM, and VANET.

  When the communication mode is specified, a route usable in each of the communication modes is specified in step 204. In step 206, a weight is assigned to each available route. For example, a greater reliability weight is given to a route via the wired communication mode than to a route following the wireless communication mode. In addition, for wired communication links that follow the shortest power line, the system costs (ie financial costs, latency, reliability, etc.) are low, so they are more important than wired communication links that do not follow the shortest power line. Give. Similarly, a greater weight is given to the wireless links of the power grid than other wireless links based on reliability. Further, the weight may be based on factors such as communication system cost and communication speed.

  In step 208, the final route of the communication can be determined based on the weight of the communication route and the objective function. This objective function can be determined by the user and can include minimizing critical customer metrics such as system costs, data transfer delays, or combinations thereof. The objective function may further include minimization of power distribution reliability indicators including but not limited to SAIDI and maifi. In another embodiment, packets of communication data may be distributed and transmitted over various routes depending on availability and desired objective function. For example, in one embodiment, if necessary, the most important information or data can be transmitted via a dedicated power grid radio, while less important information is transmitted along other wireless links. Can be done. In another embodiment, packets of communication data may be distributed and transmitted over various paths depending on availability and desired objective function. That is, data may be divided and transmitted in parallel via a combination of communication links.

  In another embodiment, communication between wireless communication links can be further enhanced by using a MAC protocol based on GPS and Geographic Information System (GIS) information. This improvement may relate to reduced message latency, reduced output, and / or increased bandwidth. Information from GPS and GIS is processed to provide an estimate of the best route to use, along with the range and output of radio frequency (RF) data that needs to be transmitted for successful communication between nodes. The GPS and GIS information can be used to provide a framework in which MAC transmission timing can be deterministically calculated, thus avoiding data collision overhead.

  In another embodiment, a multicast group can be formed in which a single packet transmission reaches all receiving nodes simultaneously to improve the efficiency of wireless communication. Data is transmitted simultaneously to multiple nodes or reclosers at the originating node, ie from the recloser where the data needs to be transferred.

  FIG. 5 illustrates a power grid communication controller system 220 according to an exemplary embodiment. This control device can be incorporated into the recloser control device 14 (FIG. 1) of each of the reclosers 36, 38, 42, 44, and 40, and can be separated from or integrated with the recloser. And / or can be incorporated into the substations 101, 46 and 48. The control device 220 includes a communication mode specifying module 222 for determining a data transmission mode that can be used between the source node and the destination node. As described above, the available modes can include a wired communication mode or a wireless communication mode. The route availability identification module 224 determines a route that can be used in each of the available communication modes determined by the module 222. The route weight assignment module 226 assigns, or provides, a weight to each available route. The weight assignment may be based on factors such as cost, communication speed, and communication reliability. The controller 220 also includes a route determination module 228 that identifies the final route of the communication based on the objective function. The control device 220 may further include a memory or storage device 230 that stores communication route information. A program database 232 is also provided for storing programs that include, but are not limited to, objective functions for processing communication routes within the distribution network. As described above, the objective function may include critical measure minimization by the consumer, such as cost, data transfer delay, SAIDI, maifi, or combinations thereof. In one embodiment, the controller 220 can utilize MAC protocols and / or multicast groups based on GPS and GIS information to optimize communications.

  As will be appreciated by those skilled in the art, the foregoing examples or portions of the foregoing examples and method steps are implemented by suitable computer program code on a processor-based system, such as a general purpose or special purpose computer. be able to. It should also be noted that in different implementations of the invention, some or all of the steps described herein may be performed in a different order or substantially simultaneously or in parallel. The computer program code is tangible, readable by one or more machines, such as an on-memory chip, a local or remote hard disk, an optical disk (ie CD or DVD), or other media, as will be appreciated by those skilled in the art. It may be stored on or adapted for storage, and these media can be accessed by a processor-based system to execute the stored code. Note that tangible media can include paper or other suitable media on which instructions are printed. For example, instructions may be captured electronically via optical scanning of paper or other media and then compiled as necessary, executed by an interpreter, or otherwise appropriately processed, It can then be stored in the computer's memory.

  While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. Therefore, it is to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

DESCRIPTION OF SYMBOLS 10 Power pole, Utility pole 12 Automatic recloser device 14 Recloser control device 30 Recloser loop system 32 Distribution feeder 34 Distribution feeder 36 Feeder recloser 38 Feeder recloser 40 Link switch, Link recloser, Link recloser open / close Equipment 42 Feeder recloser 44 Feeder recloser 46 Distribution substation 48 Distribution substation 50 Customer, customer 52 Customer 54 Customer 56 Customer 100 Recloser system 101 Substation 102 Recloser 102 Residential area 103 Industrial land 105 Recloser 106 Vehicle-to-vehicle ad hoc network 200 DA communication method 202 Step 204 Step 206 Step 208 Step 220 Power grid communication control device system, control device 222 Communication mode identification module 24 Route availability determination module 226 routes weight assignment module 228 route determination module 230 storage 232 program database

Claims (20)

A data communication method for a power grid,
Determining the available wired and wireless modes of data transmission;
Determining routes available in the available wired and wireless modes;
A data communication method comprising: assigning a weight to each of the available routes; and determining a final route for communication based on an objective function.   The method of claim 1, wherein the wired data transmission mode comprises a wired communication link through a wire.   Private wireless communication network, including, but not limited to, electric carrier wireless link, WIFI, WIMAX station, GSM, 802.11s mesh system, wireless Ethernet, 6 LowPAN, ROLL, VANET, or combinations thereof The method of claim 1, comprising at least one of: and a public wireless communication network.   Assigning the weight to each of the available routes is based on a lower system cost for a wired communication link that follows the shortest power line than a wired communication link that does not follow the shortest power line. 3. The method of claim 2, further comprising applying a greater weight.   4. Assigning the weights to each of the available routes includes assigning higher weights to utility wireless links based on reliability compared to other wireless communication modes. The method described.   The method of claim 1, wherein the weight is based on a communication system cost and communication speed via the available route.   The method of claim 1, wherein the objective function includes a minimization of a consumer index.   The method of claim 7, wherein the customer indicator includes communication system cost, data transfer delay, or a combination thereof.   The method of claim 1, wherein the objective function comprises a distribution reliability index minimization including SAIDI and maifi.   The method of claim 1, wherein the final route comprises a combination of available routes.   The method of claim 1, further comprising a media access control (MAC) protocol based on a global positioning system (GPS) and a geographic information system (GIS) in the wireless communication mode.   The method of claim 11, wherein the GPS provides a location of the node in the wireless communication mode, and the GIS provides node environment information, terrain, vegetation, and building density information.   The method of claim 11, wherein information from the GPS and the GIS provides a framework for providing the optimal route, radio frequency data range and power estimates and calculating MAC transmission timing.   The method of claim 1, further comprising a multicast group for simultaneously transmitting a single packet data to all receiving nodes. A computer readable non-transitory medium comprising computer readable computer program instructions, causing the processor to perform a method when the computer program is executed by a processor, the method comprising:
Determining the available wired and wireless modes of data transmission;
Determining routes available in the available wired and wireless modes;
Assigning a weight to each of the available routes, and determining a final route for communication based on an objective function. A device connected to the power distribution network;
A control device coupled to each of the devices,
Each control unit
A communication mode identification module for determining the available wired and wireless modes of data transmission;
A route availability identification module for determining routes available in the available wired and wireless modes;
A route weight assignment module for assigning weights to each of the available routes;
A route determination module for determining a final route for communication based on an objective function.   The system of claim 16, wherein the route weight assignment module assigns the weight based on communication system cost, communication speed, communication reliability, or a combination thereof.   The system of claim 16, wherein the objective function includes a minimization of a critical customer indicator.   The system of claim 18, wherein the critical consumer indicator includes communication cost, data transfer delay, power distribution reliability index including SAIDI and maifi, or combinations thereof.   The system of claim 16, further comprising a MAC protocol or a multicast group for optimizing the communication.

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